Hadith 4:231
'Abd al-Rahim ibn Sulayman narrated to us, from 'Abd Allah ibn Muslim, from 'Ata' and Mujahid: That when they would visit a man or be invited to a meal while they were fasting, if he asked them to break their fast, they would break it. They used to say: "We will make up a day in its place."
حدثنا عبد الرحيم بن سليمان عن عبد الله بن مسلم عن عطاء ومجاهد أنهما كانا إذا زارا رجلا أو دعيا إلى طعام وهما صائمان إن سألهما أن يفطرا افطرا كانا يقولان نقضي يوما مكانه